Power Adaptation for DVB Multiple Access Channel with Raptor Code

In this paper, we propose a scheme for increasing the capacity of forward and/or return links of the Digital Video Broadcasting Return Channel via Satellite (DVB-RCS). The increase of the capacity is achieved by overloading a pre-existing channel with a controlled interfering channel using Raptor code such that the transmission and decoding of the interfering data stream does not have any effect on the performance of the main data stream. For decoding we use successive decoding used in multi user detection methods. Since the interfering source usually does not have any information about the main channel state, we propose a power adaptation scheme which using the feedback channel of the Raptor code, estimates the channel state of the main channel and chooses the optimum power level accordingly.